Brocade Multi-Service IronWare Multicast Configuration Guide (Supporting R05.6.00) - Manual (Page 176)

164 Multi-Service IronWare Multicast Configuration Guide
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IPv6 PIM Sparse
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• The DR priority information is used in the DR election only if all the PIM routers connected to
the subnet support the DR priority option. If there is at least one PIM router on the subnet that
does not support this option, then the DR election falls back to the backwards compatibility
mode in which the router with the numerically highest IP address on the subnet is declared the
DR regardless of the DR priority values.
Passive Multicast Route Insertion
To prevent unwanted multicast traffic from being sent to the CPU, IPv6 PIM routing and Passive
Multicast Route Insertion (PMRI) can be used together to ensure that multicast streams are only
forwarded out ports with interested receivers and unwanted traffic is dropped in hardware on Layer
3 routers.
PMRI enables a Layer 3 switch running IPv6 PIM Sparse to create an entry for a multicast route (for
example, (S,G)), with no directly attached clients or when connected to another PIM router (transit
network).
When a multicast stream has no output interfaces, the Layer 3 switch can drop packets in
hardware if the multicast traffic meets the following conditions in IPv6 PIM-SM.
• The route has no OIF.
• The directly connected source passes source RPF check and completes data registration with
the RP, or the non-directly connected source passes source RPF check.
If the OIF is inserted after the hardware-drop entries are installed, the hardware entries will be
updated to include the OIFs.
NOTE
Disabling hardware-drop does not immediately take away existing hardware-drop entries, they will
go through the normal route aging processing when the traffic stops.
Configuring PMRI
PMRI is enabled by default. To disable PMRI, enter the following commands.
Brocade(config)# ipv6 router pim
Brocade(config-ipv6-pim-router)# hardware-drop-disable
To disable PMRI for a specified VRF, enter the commands as shown in the following example.
Brocade(config)# ipv6 router pim vrf blue
Brocade(config-ipv6-pim-router-vrf-blue)# hardware-drop-disable
Syntax: [no] hardware-drop-disable
Displaying hardware-drop
Use the show ipv6 pim sparse command to display if the hardware-drop feature has been enabled
or disabled.